In recent years, prepackaged, prepared foods have become increasingly popular. This has created an increasing demand for economical, simple, disposable containers, which, can provide sanitary, leak-proof containment of a variety of foods, including foods containing liquid. Paperboard cartons have been found to be an economical way to meet many packaging requirements. In particular, a number of cartons for frozen, refrigerated and shelf-stable foods have been successfully introduced that are made from paperboard coated with barriers to prevent absorption and wicking of liquids.
Although paperboard packages of many kinds are now widely sold, there are few packages that provide satisfactory performance where a tightly sealed, leak-proof carton is desired. One well-known example is the standard milk carton with a gusseted, gathered top that is sealed by joining multiple, overlapping edges in the center of one end and opened by separating a portion of the overlapping edges and unfolding one of the gussets.